Temporary surgical clipping of flow-diverted arteries in an experimental aneurysm model

OBJECTIVE Surgical management of recurrent aneurysms following failed flow diversion may pose difficulties in securing vascular control with temporary clips. The authors tested the efficacy and impact of different types of aneurysm clips on flow-diverted arteries. METHODS Six wide-necked experimental aneurysms were created in canines and treated with Pipeline flow diverters. In 4 aneurysms, occlusion of the artery at the level of the proximal and distal landing zones (n = 2 per aneurysm) was attempted, using temporary, fenestrated, single, and double permanent aneurysm clips. Two aneurysms served as unclipped controls. Serial angiography was performed to investigate the efficacy of clip occlusion, flow diverter deformation, and thrombus formation. After the animals were killed, the flow-diverted aneurysm constructs were opened and photographed to determine neointimal or device damage as a result of clip placement. RESULTS Angiography-confirmed clip occlusion was only possible for 4 of 8 of the tested flow-diverted arterial segments. Clip application attempts led to filling defects consistent with thrombus formation in 2 of 4 flow-diverted constructs, and to minor damage of the flow diverter with neointimal fracture in 1 of 4 cases. CONCLUSIONS Aneurysm clips placed on canine parent arteries bearing a Pipeline flow diverter were unable to reliably stop blood flow. Application of aneurysm clips can cause mild damage to the device and neointima, which might translate into thromboembolic risks. If possible, vascular control should be sought beyond the terminal ends of the implanted device.